Still trying to find out where George Cert is buried.
The main cemeteries for East London are
East London Cemetery, Grange Road, Plaistow 
Gibraltar Row Burial Ground, Bethnal Green 
Manor Park Cemetery, Serbert Road (1874)
Rippleside Cemetery, Ripple Road, Barking 
Romford Cemetery, Dagenham Road 
Tower Hamlets Cemetery, Southern Grove 
West Ham Cemetery, Cemetery Road.
If you go to 
http://www.cwgc.org/search/cemetery_details.aspx?cemetery=38312&mode=1and type in Cert, he comes up on the list, so I assume he will be buried at
EAST LONDON CEMETERY, PLAISTOW the one at the top of the list?